To access this work you must either be on the Smith College campus OR have valid Smith login credentials.

On Campus users: To access this work if you are on campus please Select the Download button.

Off Campus users: To access this work from off campus, please select the Off-Campus button and enter your Smith username and password when prompted.

Non-Smith users: You may request this item through Interlibrary Loan at your own library.

Publication Date

2025-5

First Advisor

Greg de Wett

Second Advisor

Luce Ward

Document Type

Honors Project

Degree Name

Bachelor of Arts

Department

Geosciences

Keywords

Paleoclimate, arctic, biomarkers, lake sediment

Abstract

BrGDGTs (branched glycerol dialkyl glycerol tetraethers) are a suite of bacterial membrane lipids whose distributions have been shown to relate to environmental temperature in modern settings. As such, they have been used to reconstruct past temperatures in sedimentary archives across a wide range of environments. Numerous questions remain, however, about the influence of environmental parameters besides temperature on brGDGT distributions (such as conductivity, pH, and dissolved oxygen). Here, brGDGTs distributions in down-core sediments from Kongressvatnet, Svalbard, Norway are analyzed. Kongressvatnet is a 55-meter deep lake, with anoxic conditions in the bottom five meters. During the 2022 and 2023 field seasons, multiple lake sediment cores were recovered from the lake. Samples from Kongressvatnet suggest brGDGTs are reflecting a signal other than temperature (likely dissolved oxygen and/or conductivity), as down-core shifts in brGDGTs do not match local and regional paleoclimate trends. Other possible controls on brGDGTs in Kongressvatnet were investigated and compared against modern sediment trap and soil samples from the lake and catchment. Although sediment type varies drastically down-core, lithology is not exerting a large influence on brGDGT distributions; other environmental parameters (possibly conductivity and/or dissolved oxygen) are likely reflected in the down-core brGDGT distributions from Kongressvatnet.

Rights

©2025 Sarah Bragdon. Access limited to the Smith College community and other researchers while on campus. Smith College community members also may access from off-campus using a Smith College log-in. Other off-campus researchers may request a copy through Interlibrary Loan for personal use.

Language

English

Comments

96 pages: color illustrations, charts. Includes bibliographical references (pages 85-96).

Download

Smith Only:
Off Campus Download

Share

COinS